The outermost surface of a conventional display device is normally a flat surface formed with a single component material of a glass layer or a transparent resin layer. In recent years, however, there has been suggested display devices each having an outermost surface that is a corrugated surface (an uneven surface) formed with constituent materials. For example, In Patent Documents 1 and 2, the outermost surface of each display device is formed by repeatedly arranging Light Emitting Diode (LED) sealing portions and unit structures formed with black-colored portions surrounding the LED sealing portions. Therefore, the LED sealing portions are not located at the same height as the surfaces of the black-colored portions, and the surface of the display device is a corrugated surface having recesses. Also, each of the LED sealing portions or the black-colored portions may not have a flat surface, and may have a corrugated surface.
At the boundary between the outermost surface of a display device and the air, external light reflection at the reflectance corresponding to the refractive index difference between the outermost surface and the air (Fresnel reflection) occurs, and as a result, photopic contrast becomes lower. Therefore, for display devices having outermost surfaces formed with corrugated surfaces as described above, there is a demand for a technology of reducing external light reflection and improving photopic contrast.